"The heads pop up on the upper right, and you can tap on them, move them around, and stack them together," Facebook CEO, Mark Zuckerberg said.

Explaining the feature, Zuckerberg said that tapping on the pop-ups brings up the user's messaging. Chatheads work with both Facebook messages and SMS, he added.

According to Facebook, the 'Chat heads' persist on the screen until the user dismisses them. "You have a Chat head listed horizontally for each notification. It switches between SMS and Facebook Messenger fairly seamlessly, like iMessage," Facebook executives explained.

In order to collapse the Chat Heads into a pile, the user needs to swipe up and then "chuck them off the bottom."

The feature also allows one to indulge in group chats, and the people in it all appear in the Chat head.

Earlier in the evening, Zuckerberg said the new software would make Facebook the home screen of Android phones, and allow the devices to be "designed around people and not apps."

"We're not building a phone and we're not building an operating system, but we are building something that's a lot deeper than an app," Zuckerberg told a gathering at the company's headquarters in Silicon Valley.

Zuckerberg started the event by saying, "Today we're finally going to talk about that Facebook phone." "Today's phones are designed around apps and not people," he added. Invitations to a press event at Facebook's main campus in the Silicon Valley city of Menlo Park rekindled talk of a "Facebook phone," but analysts had said that the social network wants to spread roots across the Android platform.